}
}
+
+// Lower dynamic stack allocation to _alloca call for Cygwin/Mingw targets.
+// Calls to _alloca is needed to probe the stack when allocating more than 4k
+// bytes in one go. Touching the stack at 4K increments is necessary to ensure
+// that the guard pages used by the OS virtual memory manager are allocated in
+// correct sequence.
SDOperand X86TargetLowering::LowerDYNAMIC_STACKALLOC(SDOperand Op,
SelectionDAG &DAG) {
+ assert(Subtarget->isTargetCygMing() &&
+ "This should be used only on Cygwin/Mingw targets");
+
// Get the inputs.
SDOperand Chain = Op.getOperand(0);
SDOperand Size = Op.getOperand(1);